Devices of this kind (David Chaum, “Security without identification: Transaction Systems to make big brother obsolete”, CHCM (28,10), October 1985, pp. 1030-1044; Stuart Stubblebine and Paul F. Syverson, “Authentic attributes with fine-grained anonymity protection”, Financial Cryptography 2000, LNCS serious, Springer-Verlag, 2000), given a careful implementation, have the property to conceal the identity of the user who is behind the pseudonym used as virtual network user, as far as possible, and for this reason the function can provide a “stealth”, under which the identity of the user of the pseudonym is hidden or at least can remain undetected.
Systems of this kind thus have the advantage that they protect protected physical persons or legal entities against publishing of personal data and properties, or even against harassment or attack efficiently, but also have the disadvantage, that a carrier of such protection deprives the state authority of lawful access and, without fear of sanctions, can develop activities, which can lead to considerable social harm.
Although it can be assumed that criminal use of such devices cannot remain hidden, and tracing the data track, which is also left by virtual network users, to its creator and thus a prosecution of crime is possible, this undertaking is however so substantially complex that it is no longer proportionate to the reasons of the rule of law, e.g. protecting the public from crime.